Improved self cleaning magnetic separator



June 6, 1961 J. J. FERRIS ETA].

IMPROVED SELF CLEANING MAGNETIC SEPARATOR Filed July 51, 1959 2Sheets-Sheet 1 fq Z June 6, 1961 J. J. FERRIS ETA!- 2,987,184

IMPROVED SELF CLEANING MAGNETIC SEPARATOR Filed July 31. 1959 2Sheets-Sheet 2 f qi 26 United States Patent 2,987,184 IMPROVED SELFCLEANING MAGNETIC SEPARATOR James J. Ferris, Upper Montclair, and JamesL. Hope, Montclair, NJ., assignors to Magnetic Engineering &Manufacturing Company, Clifton, NJ., a company of New Jersey Filed July31, 1959, Ser. No. 830,864 3 Claims. (Cl. 209223) The present inventionrelates generally to self cleaning magnetic separator.

Magnetic separators are used for many purposes, for example for removingtramp iron from coal, rock, food products and other nonmagneticmaterial. The magnetic separator comprises an endless belt conveyorhaving an upper and lower run and an electromagnet mounted therebetween.The magnetic material attracted by the magnet is carried ofI by the beltand discharged.

In order to reduce the size and weight of the magnet, it is desirable tooperate it at high power rating and high efiiciency. As the powerconsumed by the magnet results in the generation of heat, it isnecessary to dissipate the heat produced in order to avoid damaging themagnet winding.

It is an object of the invention to provide an improved self cleaningmagnetic separator having means for elfectively and efiiciently coolingthe magnet to permit it to operate with relatively high power inputwhile maintaining a safe operating temperature.

The nature, objects and advantages of the invention will be more fullyunderstood from the following description and claims in conjunction withthe accompanying drawings which show by way of example a preferredembodiment of the invention. In the drawings:

FIG. 1 is a side view of an improved self cleaning magnetic separator inaccordance with the invention.

FIG. 2 is a cross section taken approximately on the line 2--2 in FIG. 1and FIG. 3 is a partial plan view of the magnetic separator.

The preferred embodiment of the invention shown by way of example in thedrawings comprises an electrornagnet 1 having a top plate 2 and an ironcore 3 surrounded by an annular winding or coil 4 comprising a pluralityof sections separated by insulating spacers 5. The coil is supportedfrom the top plate 2 by angles 6 and rods 7. The magnet is contained inan enclosure 10 comprising the top plate 2, side plates 11, end plates12 and a bottom plate 13. The enclosure 10 is filled with a suitableliquid such as transformer oil which assists in insulating and coolingthe magnet winding. An expansion tank 14 connected to the enclosure 10by a pipe 15 maintains the enclosure completely filled whilecompensating for expansion and contraction. The sides and ends of theenclosure are provided with heat dissipating means to assist in coolingthe fluid in the enclosure. As illustrated in the drawings the coolingmeans comprises a series of tubes 16 which are of approximatelysemicircular configuration and are connected at their opposite ends withthe interior of the enclosure near the top and bottom platesrespectively. With the construction shown, fluid circulates through thetube loops 16 by convection. Warmer fluid entering the upper ends of thetubes is cooled as it flows downwardly through the tubes and isdischarged back into the enclosure at the lower ends of the tubes.

At opposite ends of the magnet enclosure 10 there are provideddrum-shaped belt pulleys 20 rotatably supported by bearings 21 carriedby frame members 22 which extend from the ends of the enclosure. Anendless conveyor belt 23 runs over the pulleys 20 and passes over andunder the magnet enclosure 10 so that the magnet is disposed betweenvthe opposite runs of the belt. Molded rubber cleats 24 extendtransversely the full width of the belt at equally spaced intervals. Thepulleys 20 have a length somewhat greater than the width of the magnetenclosure 10 and a diameter greater than the height of the magnetenclosure together with the expansion tank 14. The pulleys arepositioned so that the lower run of the belt is directly beneath and incontact with the bottom plate 13 of the magnet enclosure. The upper runof the belt is located above and spaced from the top of the enclosure.One of the pulleys is driven through a chain 25 by a motor 26 mounted ona support 2.7 which extends upwardly from the frame members 22. Thebearings of the other pulley are movable longitudinally of the framemembers 22 by take-up screws 28 to maintain the belt under propertension.

Each of the pulley drums 20 is of open construction comprising end rings30 supported by spokes 31 radiating from a hub 32 on a shaft 33. Spacedbars or slats 34 extend between the end rings 30 and constitute theperipheral surface of the drum on which the belt 23 runs. A plurality ofcircumferentially spaced vanes 35 extend longitudinally of the drumbetween the end rings 30 and are disposed approximately radially of thepulley. While the vanes 35 are shown as being flat, they may if desiredbe curved and may be inclined with respect to the radii of the pulley.The vanes do not extend all the way to the pulley shaft but terminate ata distance from the shaft, the inner edges of the vanes being forexample about midway between the shaft and the periphery of the pulley.

It will thus be seen that the pulley drums are of open construction, theends of the pulleys being naturally open and elongated openings or slotsbeing provided in the periphery between the spaced bars 34. As thepulleys rotate, the vanes 35 act as impeller blades of a blower, causingair to be drawn in through the open ends of the pulley drums anddischarged radially outwardly between the end rings and through theopenings between the bars 34. The conveyor belt running over the pulleyscloses the peripheral openings of the pulley drum except on the sidefacing the magnet enclosure 10. Hence the discharge of air from the drumis directed toward the magnet. Moreover, the upper and lower runs of theconveyor belt direct the air flow so that it is not dissipated but isconfined and guided toward the magnet enclosure. The airstream flowingover the magnet enclosure and particularly over the cooling tubes 16 ofthe enclosure greatly increases the dissipation of heat from the magnetand keeps the magnet temperature within safe limits even when the magnetis operating at a high power rating.

In operation, the magnet is suspended or otherwise supported over achute, conveyor belt or other transporting equipment carrying materialwhich is to be treated. For example the magnet may be disposed over theend pulley of a conveyor belt or alternatively may be disposedtransversely of a conveyor belt carrying the material. As the materialpasses under the magnet, any pieces or particles of iron or othermagnetic material are attracted by the magnet 1 and drawn up against theconveyor belt 23. They are thereupon carried by the belt to a pointwhere the belt passes beyond the end of the magnet, whereupon themagnetic pieces or particles are automatically discharged from the beltsince they are no longer attracted by the magnet. The pulleys 30 servethe dual purpose of supporting and driving the conveyor belt 23 and alsoacting as blowers to direct a flow of air toward the magnet enclosure todissipate heat generated by the flow of current through the magnetwinding. Moreover, the conveyor belt 23 cooperates with the pulleys indirecting the air flow not only by closing the peripheral openings inthe pulley drum on the side away from the magnet enclosure, but also inconfining the airstream and directing it toward the magnet. Theinvention thus provides efiective cooling permitting the magnet tooperate at high power rating without overheating.

While a preferred embodiment of the invention has been shown by way ofexample in the drawing, it will be understood that the invention is inno way limited to this embodiment and that many modifications may bemade in details of construction without departing from the scope andspirit of the invention.

What we claim and desire to secure by Letters Patent 2 1. In aself-cleaning magnetic separator having an electromagnet mounted betweentwo pulleys and the upper and lower runs of a belt passing around saidpulleys, an improved means for cooling said electromagnet comprising apair of combination pulley and blower each having a hub, spokes attachedto and radiating from said hub, end rings supported by said spokes saidend rings partially enclosing the ends of said pulley, spaced barsextending between said end rings forming the peripheral surface of saidpulley and defining transverse peripheral slots, a plurality ofcircumferentially spaced vanes between said end rings and extendinginwardly from said rings and adapted to create an outward radial flow ofair between said end rings and said spaced bars when said pulley isrotated, said air flow being directed toward said electromagnet by saidbelt passing around said pulley blower and leaving open the peripheralopenings directed toward said magnet.

2. An improved self-cleaning magnetic separator for separating magneticmaterial from a mixture of magnetic and non-magnetic materialscomprising; a pair of drumshaped pulleys, having ends and spacedradially apart, mounted for rotation about parallel axes, each saidpulley comprising a periphery defining a plurality of transverse slotsextending from end to end of the pulley and substantially parallel toits axis of rotation, and end rings supported at said pulley ends normalto said slots, for partially closing said ends adjacent said periphery,said end rings extending radially toward said axis of rotation; aplurality of vanes circumferentially spaced around the periphery of eachsaid pulley between said respective end rings and radially extendingfrom the associated peripheries to points intermediate the respectiveaxes of rotation, said vanes operating as impeller blades when thepulleys are rotated for drawing in air axially through the pulleys endsbetween the end rings and the axes of rotation and expelling said air inair blasts radially outwardly between said respective pulleys end ringsand through said transverse peripheral slots; an endless conveyor beltmounted on said pulleys for being driven in an upper run and a lower runaround said pulleys when at least one said pulley is rotated forconveying magnetic material, said belt closing those peripheral slots ofthe respective pulleys that are oppositely disposed to each other todirect opposed air blasts out of the opposed slots of the respectivepulleys; an electrically energized electromaguet mounted intermediatesaid pulleys and between said belt runs in said opposed air blasts formagnetically attracting magnetic material to said endless conveyor beltfrom said 'mixture passed near said belt, said electromagnet beingcooled by opposed air blasts directed thereon, whereby saidelectromagnet is operable to provide greater magnetic attraction than anuncooled electromagnet of the same size and electrical characteristics.

3. An improved self cleaning magnetic separator as described in claim 2further comprising a fluid-tight enclosure for enclosing saidelectromagnet, said enclosure having a top, a bottom, and connectingsides, and externally connecting said enclosures interior adjacent saidtop and bottom, cooling fluid means for filling said enclosure andcooling tubes, whereby said liquid, heated by said electromagnet,circulates by convection through said enclosure and pipes and is cooledin said cooling pipes by said opposed air blasts.

References Cited in the file of this patent UNITED STATES PATENTS1,400,671 Fischer Dec. 20, 1921 1,873,971 Hill Aug. 30, 1932 2,654,583Treanor Oct. 6, 1953 2,702,123 Injeski Feb. 15, 1955

